* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
header {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 100px;
  z-index: 10;
  background:#5b639c;
}
header .logo {
  position: relative;
  font-size: 1.5em;
  color: #fff;
  text-decoration: none;
  font-weight: 600;
}
header .navigation {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  margin: 10px 0;
}
header .navigation li {
  list-style: none;
  margin: 0 20px;
}
header .navigation li a {
  text-decoration: none;
  color: #fff;
  font-weight: 600;
  letter-spacing: 1px;
}
header .navigation li a:hover{
  color: #ffed3b;
}
header .search {
  position: relative;
  width: 300px;
  height: 40px;
}
header .search input {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  color: #fff;
  background: transparent;
  outline: none;
  border: 1px solid #fff;
  border-radius: 5px;
  padding: 0 10px 0 45px;
}
header .search input::placeholder {
  color: #fff;
}
header .search .fa-search {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  left: 10px;
  color: #fff;
  border-right: 1px solid #fff;
  padding-right: 10px;
}
.banner {
  background: #eee;
  padding: 200px 100px 100px;
  min-height: 100vh;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.banner .content {
  max-width: 1000px;
}
.banner .content h2 {
  font-size: 2.5em;
  color: #333;
  margin-bottom: 20px;
}
.banner .content p {
  font-size: 1em;
  color: #333;
}
.banner .content a {
  display: inline-block;
  background: #434978;
  color: #fff;
  padding: 10px 20px;
  text-decoration: none;
  font-weight: 600;
  margin-top: 20px;
}
.banner .image {
  max-width: 500px;
  margin-left: 50px;
}

@media screen and (max-width:991px){
  header{
    padding: 10px 20px;
    flex-direction: column;
  }
  .banner {
    padding: 150px 20px 50px;
    flex-direction: column-reverse;
}
.banner .image {
    max-width: 80%;
    margin-left: 0;
}
.banner .content h2 {
    font-size: 2em;
}
}
/*屏幕宽度小于600px,改变布局和样式*/
@media screen and (max-width:600px) {
  header .search {
      width: 100%;
  }
  .banner .image {
      margin-top: 30px;
  }
}